The present invention relates to a composition for the treatment or prevention of manifestations of aging containing oligosaccharides or derivatives of oligosaccharides having D-galactose in a non-reducing terminal position, these derivatives acting as modulators of the synthesis and/or the excretion of the elastase of fibroblasts.
It is known that the connective tissue in the dermis results from the biosynthetic activity of the fibroblasts which elaborate the extracellular matrix (Labat-Robert, J., et al., Elsevier Science Publisher B. V., 248: 386-393, 1990).
The extracellular matrix is composed of four families of macromolecules. These are the collagens and elastin which constitute the fibrous material of the dermis, the structural glycoproteins which provide for cohesion between the cells and the extracellular matrix and furnish the microfibrillary material of the elastic tissue, and the proteoglycans which provide for the hydration of the tissues and the control of molecular flow and interactions.
Elastin possesses a complex receptor in the membrane of the fibroblast cells which contains a 67 kD subunit which includes a binding site for the carbohydrates.
A. Hinek et al. (Science 239): 1539-1541 1988) showed that when the 67 kD subunit of the elastin receptor was immobilized on an affinity column in which the ligand was composed of elastin or peptides of elastin, lactose (1 mM) was capable of eluting this 67 kD protein, and that galactose was equally efficacious in displacing the binding of the 67 kD protein to the elastin.
On the other hand, oligosaccharides that do not contain galactose are not capable of permitting the elution of the 67 kD protein bound to the elastin affinity column.
The authors therefore concluded from this that the elastin receptor was a protein having properties of binding to galactosides.
It is also known that the elastins, in the soluble or insoluble state, are susceptible to hydrolysis by endoproteases, especially elastases.
Different classes of proteases and endopeptidases have been itemized and a review of these different endopeptidases and their properties has been published by Barrett et al., 1977 (Barrett, A. J. Eds., North Holland, Amsterdam).
The elastases are proteases and endopeptidases whose properties are beginning to be studied thoroughly. The following articles, the content of which can be incorporated into the present text by reference, describe these properties:
Bieth J. (1978) "Elastase: structure, function and pathological role". Front. of Matrix Biol. Cis.: 1-82, and PA0 Homsy, R. et al. (1988) "Characterization of human skin fibroblasts elastase activity". Journ. Invest. Dermatol. 91: 472-477. PA0 Labat-Robert, J. et al., Ann. New York Acad. Sci. (1992), 673: 16-22, PA0 Robert, J. Sang Thronrbose Vaisseaux (1991), 3: 267-330, PA0 Robert, L. Pathol. Biol. (1988), 36: 1101-1107. PA0 n represents position 1, 2, 3, 4 or 6, PA0 Hex represents a pentose or hexose linked in the .alpha. or .beta. configuration, PA0 n' is a number between 1 and 5; PA0 (I) oligoside 1--O--R, in which R is a linear or branched alkyl residue with 1 to 18 carbon atoms, PA0 (II) oligoside 1--O--R--O--1-oligoglycoside, in which R=(CH.sub.2).sub.n' n being between 2 and 10, PA0 (III) oligoside 1--NH--CO--R, in which R is an alkyl residue with 2 to 18 carbon atoms, containing 0, 1 or 2 double bonds, PA0 (IV) oligoside 1--NH--CO--R--CO--NH--1-oligoglycoside, in which R=(CH.sub.2).sub.n' n being between 2 and 8, PA0 (V) oligoside--CO--NH--R, in which R has the same meaning as in the formula (III), PA0 (VI) oligoside CO--NH--R--NH--CO--oligoglycoside, where R has the same meaning as in the formula (III), PA0 (VII) Gal--(Hex).sub.n --X--HN--R, PA0 (VIII) Gal--(Hex).sub.n --X--HN--R--NH--X-(Hex).sub.n --Gal, in which: PA0 Hex is a hexose or pentose, PA0 n=0, 1 or 2, PA0 X=1--NH.sub.2 -hexitol, and PA0 R has the same meaning as in (III). PA0 N is the number of cells in the reaction volume, PA0 T is the incubation time, and PA0 8.8 is the molar extinction coefficient corresponding to the OD of the molar solution of substrate in a cell of thickness 1 cm.
The designation of an enzyme by the name elastase does not imply that this protease is specific for elastin. In fact, the elastases hydrolyse a wide variety of protein substrates, and leucocytic elastase for example is capable of cleaving practically all the macromolecules of the connective tissue (Robert, L. 1988, Path. Biol.; 36: 1101-1107).
These proteases of the elastase type are capable of degrading the elastic fibres of the tissues as well as, moroever, other constituents such as collagen fibres or glycoproteins, for example fibronectin. This type of phenomenon has been described among the phenomena of cellular aging; numerous studies have shown that the synthesis and accumulation of this type of enzyme increases during aging, and the following may be mentioned in particular:
These same proteases and endopeptidases are also capable of degrading the matrix constituents of other organs, for example the elastin of the lungs, thus leading to pulmonary emphysema, or of degrading the elastic lamina of the arteries and the elastin and collagen of the veins, thus promoting the development of vascular diseases: atherosclerosis and ateriosclerosis of the arteries and varicose veins. All these pathologies undergo an increase in their frequency and severity with age.
Other endopeptidases of the same kind (Zn metalloendopeptidases) are capable of activating inactive angiotensin I to angiotensin II, which can trigger severe arterial hypertension.
Finally, the enkephalinases, other Zn endopeptidases of the same kind, interfere with the functioning of the enkephalins and, depending on the extent to which they are in excess, can lead to disturbances in brain function.
The common denominator of all these endopeptidases acting on different substrates and leading to very diverse pathologies is that they possess a Zn-containing active site and are all bound to the cell membrane.
In the description which follows, the case of the elastase of the fibroblasts of the skin will be discussed, but the physiopathological mechanism and the treatment principle which will be presented are also valid for the other endopeptidases and other pathologies of which the non-limiting listing was given above.